Production of stilbene derivatives and products



Unite States Patent V zrtazte I Patented Oct. 9, 1956 diaminostilbene 2,2'-disulfonic acid. The exact amount 2,766,249 of the molal excess of pyridine is not critical and any excess which has sufficient solvent power to permit carry- PRODUCTION OF AND ing out of the reaction is sufficient. The fact that the 5 pyridine reacts with the hydrochloric acid is important, Adolph J, D i t, w d liff L k d D id X, Kl i as free hydrochloric acid would tend to make the reaction Upper Montclair, N. J., assignors to Heyden Chemical reversible and lower the yield. Thus, the pyridine drives Corporation, New York, N. Y., a corporation of Delathe reaction toward completion. Ware The reaction is preferably carried out at the reflux N0 Drawing Application January 13 1955, temperature although lower temperatures may be used serial 481,712 with a consequent increase in the reaction time. Some heating is required, as the reaction rate at room tempera- 5 Claims. (Cl. 260-294r8) ture is so slow as not to be appreciable. The dipyridine reaction product has limited solubility in pyridine and can The re ent i ventio r late t a ov l method of 15 be readily separated from the reaction mixture by cooling producing salicoyl derivatives of 4,4'-diamino stilbene the reaction mixture followed by filtration to separate the 2,2'-disulfonic acid and to the novel derivatives obtained. p pi pr ct which is an important advantage. Certain benzoyl chloride compounds substituted in the Preferably, Separated Product is Washed With a strong ortho position have been reacted with 4,4'-diaminostilacid, for p hydrochloric sulfuric, acetic or like bene 2,2'-disulfonic acid to form the corresponding diacid, to dissolve and remove the accompanying py benzoyl compounds. For example, o-acetyloxy benzoyl and the acid-washed product may be washed additionally chloride (cfl coofl l-l cocl) the b l with water to remove impurities. In this manner, the chloride (CHsOCsHCOCD can be reacted with 4,4'- dipyridine salt may be produced i high yield and in a diaminostilbene 2,2-disulfonic acid to form 4,4-di(ohigh degree of P yacetyloxy)-benzoyl diaminost-ilbene 2,2-disulfonic acid The dipyridihe Salt of 4,4'sdisalicoylamihostilbehe 3'' 4 4'- i -b l i i ilb zgcdi ldisulfonic acid may be used as an optical bleach for cellufonic acid. Such a reaction is carried out in an a ueous iosic materials, such as cotton, P p linen and the like, medium containing sodium hydroxide or other alkaline which Kind to develop undesirable yellowish Cast With compound hi h n ut li th h d hl i id age. This dipyridine salt has been found to be particuf d during h reaction larly useful for treating cellulosic fibrous material, such as salico l chloride, o-hydroxy benzoyl chloride, can not pape where the material i not subjected to subsequent be reacted with 4,4'-di-aminostilbene 2,2'-disulfonic acid Washing With dhtefgeht's and when pp from y in the manner described above to produce 4,4'-disalicoyldilute aqueous Solutionsaminostilbene '2,2-disulfonic acid in a satisfactorily high The py Salt of 4,4'-disalicoylamihosfilhehe i ld, Th hydpoxyl OI-I) group renders h dj disulfon-ic acid can be readily converted to the corre- COC1) group highly ti so that th li l sponding salt of an alkali metal or alkaline earth metal chloride is readily converted to salicylic acid in the presy h'hatmehi with an alkaline compound of one of these ence of water and this acid will react with any alkaline metals, Such as an alkali metal an alkaline earth ycompound present to form the corresponding salicylate. dIOXide icarhohate- For p py Salt We have discovered that salicoyl chloride can be re- 40 may p in Water and Sodium hydroxide added a t d ith 4,-4'.di i ti1b 2,2'-di 1f id i th to form the disodium salt of 4,4-disal-icoylaminostilbene presence of pyridine To produce in high yield the djpyri. 2,2'-dlSlllfOI1lC acid. The liberated pyridine may, but not dine salt of 4,4-disalicoylaminostilbene 2,2'-disulfonic necessarily be removed y means of a selective solvent acid. This reaction can be represented by the following and then the disodium Salt may he recovered in y Shit equation: 5

OH 110 on nae-@wrncnQ-rmw e u a $03K $03K H 0 H H fil) QM. diam MC} H S0;H.N coin-N $11 2HC1-N HO OK no CH Ho CH mi as Ht as al a. H H H In accordance with the above reaction, 2 moles of salicoyl chloride and 4 moles of pyridine are required for each able manner. A soluble alkali metal salt, sodium chlomole of 4,4-diaminostilbene 2,2-disull:onic acid. An exride, may be added to the aqueous solution to precipitate cess of salicoyl chloride is preferably used to increase the the product by means of a salting out procedure. The yield based on the amount of the substituted stilbene precipitated product can be separated by filtration, used. An excess of pyridine is required as it acts as a. washed, preferably with an alkaline aqueous solution, and solvent for the reaction in addition to forming a salt with thereafter dried. The alkaline salt, such as the disodium the two sulfonic acid groups and tying-up the hydrosalt, may be converted to the free base by treatment with chloric acid. The pyridine apparently dissolves the salicoyl chloride and at least partially dissolves the 4,4-

a strong acid which is stronger than the sulfonic acid groups. 

1. THE DIPYRIDINE SALT OF 4,4''-DISALICOLYAMINOSTILBENE 2,2''-DISULFONIC ACID. 